The invention relates generally to surface mounted connectors, and more specifically, to a socket connector assembly that is mounted to a circuit board.
The ongoing trend toward smaller, lighter, and higher performance electrical components and higher density electrical circuits has led to the development of surface mount technology in the design of printed circuit boards and electronic packages. Surface mountable packaging allows for a separable connection of a package, such as a computer processor, to pads on the surface of the circuit board rather than by contacts or pins soldered in plated holes going through the circuit board. Surface mount technology may allow for an increased component density on a circuit board, thereby saving space on the circuit board.
One form of surface mount technology includes socket connectors. A socket connector may include a substrate with conductive terminals on one side of the connector and an array of conductive solder elements on the opposite side. The substrate includes vias that are plated with a conductive material to provide conductive pathways through the substrate. The terminals are joined with the vias on one side of the substrate and the solder elements are joined with the vias on the opposite side of the substrate. The terminals engage contacts on an electronic package, such as a processor, and the solder elements are affixed to conductive pads on a circuit board to electrically join the electronic package with the circuit board.
As the need for smaller, lighter, and higher performance electrical components and higher density electrical circuits increases, the need for smaller vias in the substrates of the socket connectors increases. For example, increasing the number of conductive vias through the substrate may increase the number of available terminals to engage contacts of the electronic package. More conductive vias may enable transfer of data at a faster rate.
But, increasing the number of vias in the substrate introduces problems. The size of the substrate may be limited. Increasing the number of vias may require increasing the density of the vias by reducing the via pitch distance and reducing the diameters of the via holes. Decreasing the hole diameters increases the aspect ratio of the holes. If the aspect ratio of the holes becomes too large, it can become difficult to reliably plate the walls of the holes in the substrate. For example, holes that are too narrow throughout the thickness of the substrate may not allow for a conductive plating material to coat or plate the wall of the hole along the entire thickness of the substrate. If the conductive plating does not extend all the way through the thickness of the substrate, then the vias may not electrically couple the terminals with the solder elements on opposite sides of the substrate. Additionally, decreasing the pitch distance between the vias reduces the surface areas of the via land diameters that are used to connect terminals to the vias. If the land diameters become too small, the vias may not have enough surface area for terminal connection.
A need exists for a socket connector assembly that provides a greater density of conductive pathways through the thickness of a substrate in the assembly.